1. Field of the Invention
The present invention relates to a substrate for a surface material, to a surface material and to a molded body. More specifically, it relates to a surface material substrate, surface material and molded body with excellent design properties, flame retardancy, mold releasability, followability and trimming properties, which can be used favorably as a surface material substrate, surface material and molded body for automotive applications.
2. Related Background Art
Conventionally, needle-punched nonwoven fabric impregnated with vinyl chloride binder, acrylic binder or polyester binder has been used as surface materials for automobile insulators (Patent Documents 1 to 4). Such a surface material is molded as a unit with a substrate mat consisting of resin felt, cardboard, plastic foam, fiberglass resin composite, wood stock or rigid nonwoven fabric for use in various automotive parts. One method of molding such a surface material with a substrate mat as a unit is by heat pressing. This heat pressing is a molding method in which the surface material and substrate mat are integrated together by using a pair of molds to apply heat and pressure to the laminated surface material and substrate mat. The resulting integrated molded body can then be trimmed around the edges with a blade and used for various automotive parts.
When using a surface material impregnated with a vinyl chloride binder, it has happened that the surface material sticks to the mold during heat pressing when the surface material and substrate mat are molded as a unit by such a heat press method, resulting not only in poor mold releasability but also in poor followability of the surface material to the shape of the mold, causing delamination and wrinkling due to peeling of the substrate mat, and detracting from the surface quality.
As in the case of the vinyl chloride binder, the surface material may also stick to the mold when using a surface material impregnated with an acrylic binder, detracting from the mold releasability, and the surface material may be pulled or shredded by the cutting blade when the molded body is trimmed around the edges with a blade after being molded as a unit, so that the surface material and substrate mat separate from the shredded areas. In other words, the trimming properties have been poor.
In the case of a surface material impregnated with a polyester binder, the surface material may stick to the mold during heat pressing as it does when using a vinyl chloride binder, resulting in poor mold releasability. In any of these cases, the necessary flame retardancy for automotive use may not be satisfied depending on the types of materials constituting the substrate mat and/or whether or not a flame retardant is used.
Therefore, the inventors of the present application have proposed “a substrate for a surface material, wherein one surface of a fiber substrate containing cellulosic fibers is bonded by a polyester resin binder containing a flame retardant and a thermosetting resin” (Patent Document 5). This substrate for a surface material had excellent design properties, flame retardancy, mold releasability, followability and trimming properties.    Patent Document 1: Japanese Patent Publication No. H7-030515 (Claims, Column 4 Lines 8 to 20)    Patent Document 2: Japanese Patent No. 3212853 (Claims, paragraphs 0022 to 0023)    Patent Document 3: Japanese Patent Application Laid-open No. H6-278260 (paragraph 0033)    Patent Document 4: Japanese Patent Publication No. H7-072394 (Claims, column 4 lines 29 to 32)    Patent Document 5: Japanese Patent Application Laid-open No. 2009-78375 (Claims)